Brief Summary

Description

Thallus: adnate to loosely adnate appressed or somewhat raised at the periphery, foliose, up to 7 cm diam., lobate; lobes: short and rounded to somewhat elongate and angular, discrete to contiguous or subimbricate, 1-3 (-4) mm broad, flat; upper surface: olive-brown to dark reddish-brown, smooth to weakly rugose or pitted at the periphery, inward usually even more so, occasionally developing scattered papillae or tubercles; dull throughout or slightly shiny at the periphery; occasionally pruinose in scattered areas; usually with pseudocyphellae only on the occasional tubercles; lower surface: dark brown to black, sometimes pale tan at the periphery or (rarely) throughout; smooth to distinctly rugulose or weakly traberculate; usually somewhat shiny; moderately to densely rhizinate, the rhizines ± concolorous with the lower surface; Apothecia: common, up to 4 mm diam., sessile, concave to flat or somewhat convex with age, the margin entire to tuberculate, the tubercles usually pseudocyphellate; asci: clavate, 12-32 (usually c. 26)-spored; ascospores: subglobose to broadly ovoid or ellipsoid, 5.5-10 (-11.5) x 5-8 µm; Pycnidia: common, immersed; conidia: acerose to slightly fusiform, 5-8 x 1 µm; Spot tests: cortex K-, C-, KC-, P-, HNO3-; medulla K-, C-, KC-, P-; Secondary metabolites: none detected.; Substrate: bark of shrubs or trees; World distribution: west coast of North America, south-central Alaska to southern California; Sonoran distribution: southern California.; Notes: Based on external morphology alone, this species is not consistently distinguishable from closely related M. subolivacea. However, fertile specimens are easily identified by their 12-32 ascospores occurring in each ascus. Melanelia multispora also has a narrower distribution in western North America, and is not found in the main part of the study area.